SB 

94-5 


Injuries  to  Forests  and 
Forest  Products  by 
Roundheaded  Borers. 
J.L.Webb 


IRLF 


SB  bfl 


Y.  B.  Separate  542. 


JURIES  TO  FORESTS  AND  FOREST  PRODUCTS 
BY  ROUNDHEADED  BORERS. 


J.  L.  WEBB, 

Agent  and  Expert,  Forest  Insect  Investigations,  Bureau  of  Entomology. 


[FROM  YEARBOOK  OF  DEPARTMENT  OF  AGRICULTURE  FOR  1910.] 


97236°— 11 


CONTENTS. 


Page. 

Forest  insect  depredations 341 

Roundheaded  borers 341 

Economic  importance 342 

Character  of  work 342 

Life  history  and  habits 342 

Seasonal  history 344 

The  western  larch  bark-borer 344 

The  southern  pine  sawyer 346 

The  locust  borer 347 

The  painted  hickory  borer 349 

The  black-horned  pine-borer 350 

The  cedar-tree  borer 351 

The  western  cedar  bark-borer 352 

The  banded  ash  borer 353 

The  red-headed  clytus 354 

The  oak  pruner 355 

The  hickory  twig-girdler 356 

Summary . 357 


Main  Lib, 

ILLUSTRATIONS. 


PLATE. 

Page. 

PLATE  XXIII.  Work  of  the  black-horned  pine-borer  (Callidium  antennatum] .  348 

TEXT    FIGURES. 

FIG.  19. — Work  of  the  western  larch  bark-borer  (Tetropium  velutinum) 343 

20. — Work  of  the  western  larch  bark-borer  ( Tetropium  velutinum) 345 

21. — Work  of  the  southern  pine  sawyer  (Monohammus  titillator) 346 

22. — Work  of  the  locust  borer  ( Cyllene  robinise) 347 

23. — Work  of  the  painted  hickory  borer  ( Cyllene  caryse) 349 

24. — Work  of  the  cedar- tree  borer  ( Hylotrupes  ligneus) 351 

25. — Work  of  the  western  cedar  bark-borer  (Hylotrupes  amethystinus) 352 

26. — Work  of  the  banded  ash  borer  ( Neodytus  caprxa) 353 

27. — Work  of  the  red-headed  clytus  (Neodytus  erythrocephalus) 354 

28. — Work  of  the  oak  pruner  ( Elaphidion  villosum) 355 

29. — Work  of  the  hickory  twig-girdler  ( Oncideres  cingulata} 356 

ii 


INJURIES    TO    FORESTS    AND    FOREST    PRODUCTS    BY 
ROUNDHEADED  BORERS. 

By  J.  L.  WEBB, 
Agent  and  Expert,  Forest  Insect  Investigations,  Bureau  of  Entomology. 

FOREST  INSECT  DEPREDATIONS. 

In  recent  years  much  stress  has  been  laid  upon  the  conservation  of 
natural  resources  in  the  United  States.  Of  these  resources,  the  forests 
have  probably  absorbed  more  attention  than  any  other.  Vast  areas 
have  been  set  aside  from  the  public  domain  as  National  Forests  in 
order  that  the  timber  supply  of  the  county  shall  not  become  ex- 
hausted. Much  has  been  said  on  the  subject  of  damage  by  fire  to  the 
forests,  and  it  is  fully  realized  that  this  is  an  ever-present  danger. 
But  a  more  insidious  and  equally  relentless  foe  of  the  forests  is  found 
in  the  form  of  insects  which  work  terrible  destruction,  often  unno- 
ticed until  the  damage  is  done.  The  immense  destruction  to  living 
forests  by  certain  scolytid  barkbeetles,  as  well  as  the  injurious  work 
of  flat-headed  borers,  have  been  given  attention  in  former  Yearbook 
articles.  In  this  article  another  group  containing  many  injurious 
species  is  discussed,  namely,  roundheaded  borers.  The  information 
conveyed  in  this  paper  is  based  almost  entirely  on  the  material  and 
records  of  the  forest  insect  collection  of  the  Bureau  of  Entomology. 

ROUNDHEADED   BORERS. 

Eoundheaded  borers  are  so  called  to  distinguish  them  from  the 
flat-headed  borers.1  The  general  appearance  is  that  of  an  elongate, 
fleshy,  yellowish-white  grub,  sometimes  bearing  three  pairs  of  legs 
and  sometimes  without  legs.  The  head  is  more  or  less  oval  in  shape, 
though  sometimes  elongate,  and  often  deeply  retracted  within  the 
lirst  prothoracic  segment,  which  is  situated  immediately  behind  the 
head.  The  head  is  provided  with  a  strong  pair  of  jaws  or  mandibles, 
brown  or  black  in  color,  for  cutting  through  plant  tissue.  Some  spe- 
cies mine  only  in  the  bark  of  trees,  some  mine  in  both  bark  and 
wood,  and  some  confine  themselves  to  herbaceous  plants.  In  each 
case  the  borer  is  hatched  from  an  egg  laid  upon  or  in  the  bark  or 


1  See  "  Injuries  to  forest  trees  by  flat-headed  borers,"  Yearbook,  1909,  p.  399. 

341 


342  YEARBOOK   OF   THE   DEPARTMENT   OF   AGRICULTURE. 

wood  by  the  parent  beetle.  It  lives  and  feeds  entirely  within  the 
bark  or  wood  until  it  attains  its  full  growth,  when  it  changes  to  the 
pupa,  or  resting  stage,  within  its  burrow.  The  pupa  later  transforms 
to  a  beetle,  which  emerges  and  flies  in  search  of  suitable  places  to 
repeat  the  process  of  propagating  the  species.  In  nearly  every  in- 
stance the  entire  damage  is  done  while  the  insect  is  in  the  grub,  or 
borer,  stage.  This  form  is  therefore  the  most  important  from  an  eco- 
nomic standpoint. 

ECONOMIC   IMPORTANCE. 

Some  species  of  roundheaded  borers  kill  trees  outright  by  mining 
in  the  bark,  thus  destroying  the  vitality  of  the  tree,  while  others 
injure  the  wood  of  dead,  dying,  or  felled  trees,  or  timbers  manufac- 
tured from  such  trees.  Still  others  both  kill  the  trees  and  injure  the 
wood  for  commercial  purposes.  The  annual  loss  to  owners  of  forest 
trees  and  forest  products  from  this  source,  if  figured  up  in  dollars 
and  cents,  would  amount  to  a  sum  far  in  excess  of  what  the  ordinary 
individual  would  think  possible. 

CHARACTER  OF  WORK. 

The  work  of  this  class  of  insects  usually  appears  as  irregular  wind- 
ing mines  or  "  wormholes  "  in  the  bark  and  wood.  The  mine  always 
starts  in  the  bark,  where  the  minute  larva  just  hatched  from  the  egg 
starts  to  bore  and  feed.  At  first  the  mine  is  very  small,  but  gradually 
becomes  larger  as  the  borer  advances  and  grows  in  size.  As  already 
indicated,  the  work  of  some  species  is  confined  entirely  to  the  bark. 
The  work  of  other  species  is  found  in  both  bark  and  wood.  In  this  case 
the  mine  is  continuous  from  bark  to  wood,  the  entrance  into  the  wood 
being  a  flattened  oval  hole.  That  part  of  the  mine  which  is  in  the 
wood  may  be  long  or  short,  according  to  the  species.  In  general  it  is 
more  or  less  winding  and  irregular,  contains  borings  and  woody  excre- 
ment, and  finally  broadens  out  into  a  cell  or  "  pupal  chamber."  At  the 
farther  end  of  this  cell  the  mine,  or  "  exit  burrow  "  as  it  now  becomes, 
usually  leads  directly  to  the  surface  by  the  shortest  route.  Upon  the 
surface  it  usually  appears  as  a  perfectly  round  "  exit  hole  "  (fig.  21,  d). 

LIFE  HISTORY  AND  HABITS. 

As  a  usual  thing  the  adult  female  beetle  lays  an  egg  or  a  cluster  of 
eggs  either  in  or  upon  the  bark  in  the  spring,  summer,  or  early  fall. 
Sometimes  the  parent  female  excavates  a  pit  in  the  bark  with  her 
mandibles,  through  which  the  eggs  are  thrust  by  means  of  the  ovi- 
positor. In  other  cases  eggs  may  be  deposited  in  crevices  of  the  bark 
or  under  the  overlapping  scales  of  bark.  In  a  few  days  after  the  egg  is 


INJURIES   BY   ROUNDHEADED   BORERS. 


343 


deposited  a  minute  wormlike  larva  (fig.  19,  c)  issues  therefrom  and 
immediately  begins  boring  into  the  bark  with  which  it  finds  itself  in 
contact.  The  larva  usually  proceeds  directly  to  the  inner  bark,  or 
cambium,  immediately  next  to  the  wood.  Here  the  larva  mines  and 
feeds  until  it  reaches  a  certain  growth,  when  it  makes  preparation  for 
a  change  called  pupation.  The  entire  growth  of  the  insect  is  attained 
in  the  larval  form. 
Usually,  before  it  at- 
tains full  growth,  how- 
ever, the  larva  mines 
either  into  the  solid 
wood  or  into  the  outer 
corky  bark  and  digs  out 
an  elongate  oval  cell, 
in  which  it  will  soon 
pupate.  From  the  far- 
ther end  of  the  pupal 
cell  the  larva,  as  a  gen- 
eral thing,  extends  the 
mine  almost  to  the  sur- 
face of  the  tree  or  log, 
in  order  to  facilitate  its 
emergence  into  the  open 
air  when  it  has  gone 
through  its  changes  in 
the  pupal  cell  to  the 
adult  or  beetle  form. 
This  work  completed,  it 
retires  to  the  pupal  cell 
and  awaits  the  change 
to  the  pupal  form. 
Finally  the  outer  skin 
comes  off  and  the  insect 
lias  an  entirely  different 
form  and  appearance 
(fig-  20,  d).  It  is  now 
a  pupa.  The  length  of 
time  passed  in  this  form 
is  variable  with  the 
species  and  with  the  local  conditions,  the  pupa  resting  perfectly 
quiescent  in  its  cell  during  this  period.  At  length  another  change 
takes  place  and  the  insect  is  in  the  adult  or  beetle  stage  (fig.  20,  5). 
At  first  the  beetle  retains  the  white  color  of  the  pupa  and  ^arva,  and 
the  outer  tissue  of  the  body  is  quite  soft.  But  gradually  the  color 
turns  darker  and  the  outer  tissue  becomes  hard  and  chitinous.  When 


FIG.  19. — Work  of  the  western  larch  bark-borer  (Te- 
tropium  velutinum).  Sections  of  bark  of  western 
larch :  a,  Cluster  of  eggs  deposited  under  overlap- 
ping scale  of  outer  bark,  the  overlapping  scale,  in 
this  instance,  having  been  removed  ;  6,  inner  surface 
of  bark  with  newly  started  mines  ;  c,  small  larva,  a 
few  days  old.  Slightly  enlarged.  (Original.) 


344  YEARBOOK   OF   THE  DEPARTMENT   OF   AGRICULTURE. 

fully  hardened  and  mature  the  young  beetle  crawls  into  the  mine 
leading  away  from  the  pupal  cell  and  completes  this  mine  to  the  sur- 
face of  the  tree  or  log.  It  then  flies  away.  Mating  and  egg  laying 
soon  follow  to  provide  for  another  generation. 

SEASONAL,    HISTORY. 

Probably  in  the  great  majority  of  cases  the  larva  does  not  change 
to  the  pupa  until  the  spring  following  the  season  in  which  the  egg 
is  laid,  passing  the  winter  either  in  the  larval  mine  or  in  the  pupal 
cell.  However,  pupation  may  take  place  in  the  fall  and  the  winter 
be  passed  in  this  stage,  or  the  adult  stage  may  be  reached  in  the  fall 
and  the  winter  be  passed  in  this  form  within  the  pupal  cell.  The 
following  spring  the  larvae  which  have  wintered  over  transform  to 
pupae.  The  pupae  soon  transform  to  adults  and  the  adults  emerge 
and  take  flight.  Likewise,  the  pupae  which  have  wintered  over  trans- 
form to  adults  and  emerge.  The  first  to  emerge,  however,  are  those 
individuals  which  have  wintered  over  as  adults.  Sometimes  a  spe- 
cies may  have  two  generations  a  year,  or  a  partial  second  genera- 
tion. In  these  cases  development  takes  place  rapidly  after  the  eggs 
are  laid  in  the  spring,  the  adult  insects  of  the  first  generation  emerg- 
ing in  late  summer  or  fall,  and  laying  eggs  for  the  second  generation. 
The  second  generation  passes  the  winter  as  outlined  above.  In  still 
other  and  more  rare  cases  two  or  more  years  may  be  necessary  for  the 
complete  development  of  certain  species. 

THE    WESTERN    LARCH    BARK-BORER. 

(Tetropium  velutinum  Lee.) 

At  the  present  time  the  western  larch  bark-borer  is  quite  a  serious 
pest  in  the  Glacier  National  Park  in  Montana.  In  the  vicinity  of 
Lake  McDonald  about  10  per  cent  of  the  stand  of  western  larch  or 
tamarack  is  being  killed  annually  by  this  bark-borer.  Besides  larch 
it  attacks  fir,  Douglas  fir,  western  hemlock,  and  pine,  in  the  Rocky 
Mountain  and  Pacific  coast  regions. 

The  eggs  are  deposited  in  clusters  under  overlapping  scales  of  bark 
(fig.  19,  a)  and  the  minute  larvae  hatching  therefrom  proceed  to  the 
inner  bark,  where  they  immediately  commence  their  mines  (fig.  19,  &). 

The  work  of  this  borer  in  larch  is  confined  to  the  bark,  though  in 
some  of  the  other  host  trees  mentioned  above  it  sometimes  enters  the 
sapwood.  The  larval  mine  is  irregular  and  winding  in  the  inner 
bark.  The  number  of  mines  is  so  great  as  to  completely  girdle  the 
tree  and  cut  off  the  sap,  thereby  causing  the  death  of  the  tree.  Often 
almost  the  entire  inner  layer  of  bark,  or  cambium,  is  destroyed  for 
quite  a  considerable  space  upon  the  trunk  (fig.  20.  a). 


INJURIES   BY  ROUNDHEADED   BORERS. 


345 


The  grub  (fig.  20,  c)  is  elongate  and  somewhat  cylindrical,  yellowish 
white  in  color,  and  about  1  inch  long  when  full  grown.  Its  mouth- 
parts  are  dark  brown  to  black,  and  the  under  side  of  the  body  is  pro- 
vided with  three  pairs  of  minute  legs.  It  lives  in  the  bark  about  a 
year,  emerging  in  the  spring  or  summer  as  an  elongate,  brownish 
to  black  beetle  (iig. 
20,  6),  the  surface  of 
the  body  having  a 
velvety  appearance. 
The  beetle  ranges  in 
length  from  9  to  19 
mm.1  The  principal 
time  of  emergence  is 
May  and  June.  This 
species  attacks  either 
healthy,  injured,  or 
felled  trees. 

The  methods  of 
control  are  preven- 
tive. Once  a  tree  is 
badly  infested  noth- 
ing can  be  done  to 
save  that  particular 
tree.  Something  can 
be  done,  however,  to 
stop  the  spread  of 
the  infestation  to 
other  trees.  Infested 
trees  should  be  felled 
and  barked  and  the 
bark  burned  before 
May  15.  Something 
could  also  be  accom- 
plished by  the  use  of 
trap  trees.  As  the 
insect  breeds  readily 
in  felled  trees,  a  few 
healthy  trees  felled  in  May  or  June  near  those  infested  would  attract 
the  beetles  which  would  otherwise  deposit  their  eggs  in  healthy  trees. 
Later  in  the  season,  or  before  the  following  spring,  the  bark  should 
be  stripped  off  the  trap  trees  and  burned. 


a 


FIG.  20. — Work  of  the  western  larch  bark-borer  (Tetropium 
velutinum).  Section  of  bark  of  western  larch:  a,  Com- 
pleted larval  mines  in  inner  bark ;  6,  adult  beetle ;  c, 
larva ;  d,  pupa.  Insects  approximately  natural 
(Original.) 


size. 


1 1  mm. =5^  inch. 


346  YEARBOOK  OF  THE  DEPARTMENT   OF  AGRICULTURE. 

THE    SOUTHERN    PINE    SAWYER. 
(Monahammus  titillator  Fab.) 

Within  recent  years  the  States  of  the  extreme  south  have  suffered 
severely  from  cyclones  and  other  windstorms.  An  immense  amount 
of  pine  timber  has  been  felled  by  these  storms.  In  practically  every 
case  great  damage  has  been  done  to  the  fallen  timber  by  the  southern 
pine  sawyer  over  the  entire  area  covered  by  the  storm.  It  has  been 
estimated  that  during  the  years  1906,  1907,  and  1908  the  pecuniary 
loss  from  this  source  in  the  Southern  States  was  over  $ 


FIG.  21. — Work  of  the  southern  pine  sawyer  (Monohammus  titillator).  Section  of 
trunk  of  storm-felled  longleaf  pine,  showing :  a,  Egg  pit  in  bark  ;  6,  entrance  hole  of 
larva  into  wood  ;  c,  pupal  cell ;  d,  emergence  hole  ;  e,  g,  h,  sections  of  larval  mines ; 
f,  scored  surface  of  wood,  scoring  done  by  larva  preparatory  to  entering  wood  ;  i,  larva  ; 
/,  adult.  Insect  one-half  natural  size.  (Original.) 

This  insect  never  attacks  healthy  trees,  but  only  those  already 
dead,  dying,  or  felled.  The  damage  to  each  tree  or  log  is  the  work 
of  the  larvae  or  grubs  which,  after  first  mining  in  the  bark,  mine  in  and 
through  the  sapwood,  and  even  penetrate  the  heartwood,  making  large 
unsightly  holes  (see  fig.  21)  which  cause  the  lumber  made  from  this 
portion  of  the  log  to  be  thrown  into  the  lowest  grade,  known  to  the 
lumberman  as  "  No.  2  common."  The  larva  is  an  elongate,  footless, 
white  grub  (see  fig.  21,  i).  The  size  varies  considerably  in  different 

1  U.  S.  Dept.  of  Agriculture,  Bureau  of  Entomology,  Bui.  58,  Part  IV,  p.  45. 


INJURIES   BY   KOUNDHEADED   BOREKfcf. 


347 


individuals  and  according  to  age.  The  largest  at  maturity  have  been 
found  to  measure  slightly  over  60  mm.  in  length  and  9  mm.  in 
breadth  at  the  broadest  point.  It  appears 
that  normally  there  is  one  generation  of  this 
species  per  year,  with  a  partial  second  genera- 
tion. Thus,  a  few  larvae  hatched  from  eggs 
deposited  in  the  spring  go  through  their 
changes  to  the  adult  form  and  the  adults 
emerge  in  the  fall,  while  the  larger  number 
of  the  larvae  hatched  from  eggs  deposited  in 
the  spring  and  summer  hold  over  until  the 
following  spring,  when  the  adults  emerge. 
The  adult  (fig.  21,  j)  is  an  elongate  beetle 
varying  from  16  to  31.5  mm.  in  length  and 
from  5  to  10  mm.  in  width.  The  color  is  a 
mottled  gray  and  brown.  In  the  male  the 
antennae  ("horns")  are  very  long,  often  be- 
ing two  or  three  times  the  length  of  the 
beetle.  In  the  female  they  are  much  shorter. 
The  principal  time  of  emergence  in  the 
Southern  States  seems  to  be  March  and 
April. 

Injury  to  felled  pine  timber  by  this  species 
may  be  prevented  in  two  ways.  First,  by 
placing  infested  logs  in  water  while  the 
larvae  are  still  in  the  bark  and  before  they 
have  entered  the  wood;  and  second,  by  re- 
moving the  bark  from  the  logs  before  the 
larvae  have  entered  the  wood. 

Trees  or  logs  infested  by  this  borer  can  be 
readily  recognized  by  the  pits  (fig.  21,  a)  ex- 
cavated in  the  bark  by  the  female  prepara- 
tory to  depositing  eggs. 


THE    LOCUST   BORER. 


(Cyllene  robinicc  Forst.) 


FIG.  22.— Work  of  the  lo- 
cust borer  (Cyllene  ro- 
Mniw).  Section  of  trunk 
of  dying  locust,  showing 
larval  mines  :  a,  Larva ; 
6,  adult.  Insects  natural 
size.  (Original.) 


So  important  and  destructive  an  enemy  of 
the  black  or  yellow  locust  has  the  locust  borer 
become  that  in  certain  sections  of  the  country 
the  growing  of  these  trees  has  been  considered 
unprofitable  because  of  the  widespread  depredations  of  the  borer. 
Throughout  the  Eastern  and  Middle  States  scarcely  a  community 
where  locust  triees  occur  is  exempt  from  this  insect.  Many  trees  are 
97236°— 11 2 


348  YEARBOOK   OF    THE   DEPARTMENT    OF   AGRICULTURE. 

killed  outright,  and  in  others  the  wood  is  generally  reduced  in  value 
for  commercial  purposes. 

So  far  as  known,  this  species  confines  itself  to  the  black  or  yellow 
locust.  The  borer  is  an  elongate,  compact,  yellowish-white  grub  or 
larva  furnished  with  three  pairs  of  minute  legs  (fig.  22,  a).  Its 
first  work  is  done  in  the  inner  bark,  where  it  destroys  a  portion  of  the 
vital  tissues.  Later  it  enters  the  wood  to  feed  and  pupate.  It  is 
here  that  its  most  destructive  work  is  done,  either  by  so  honeycombing 
the  wood  as  to  cause  the  death  of  branches  or  small  trees  or  by 
injuring  the  wrood  for  commercial  purposes  (fig.  22).  The  egg  from 
which  the  borer  is  hatched  is  deposited  by  the  adult  female  in  a 
crevice  of  bark  on  the  trunk  or  a  branch,  between  the  middle  of 
August  and  the  middle  of  October.  The  larva  passes  the  winter  in 
the  bark,  where  it  lies  dormant  in  a  hibernating  cell  of  its  own 
construction.  In  the  spring  (usually  about  the  second  week  in  April 
in  the  vicinity  of  Washington)  activity  commences  again  and  the 
borer  leaves  the  hibernating  cell  to  feed  on  the  inner  bark  and  outer 
wood.  In  from  two  weeks  to  a  month  it  enters  the  wood,  where 
it  continues  to  feed  and  later  changes  successively  to  pupa  and  adult 
(fig.  22,  b).  Adults  begin  emerging  from  the  trees  in  August  and 
continue  emerging  till  the  last  of  September,  the  principal  period  of 
emergence  being  the  last  half  of  August  and  first  half  of  September. 
The  adult  is  an  elongate  beetle,  the  ground  color  of  which  is  black, 
with  numerous  cross-bands  of  yellow.  Within  a  few  hours  after 
emergence  copulation  takes  place  and  the  females  begin  depositing 
eggs.  There  is  but  one  generation  a  year. 

The  adults  are  usually  common,  feeding  on  the  flowers  of  goldenrod 
while  this  plant  is  in  bloom. 

When  infested  trees  are  so  badly  damaged  as  to  be  worthless  they 
should  be  cut  down  in  May  and  June  and  burned  to  kill  the  broods 
of  larvae.  At  this  time  all  such  trees  can  be  easily  recognized  by  the 
boring  dust  which  is  thrown  out  by  the  larvas  and  lodges  in  forks  of 
trees,  in  crevices  of  bark,  and  on  the  ground  underneath.  They  can 
also  be  recognized  by  the  fading  leaves,  broken  branches,  etc.  This 
work  should  be  completed  by  the  time  the  flowers  have  all  fallen  from 
the  trees,  or  before  the  earliest  varieties  of  goldenrod  begin  to  show 
evidences  of  flowering. 

Hibernating  larvaB  may  be  killed  by  spraying  the  trunks  and 
branches  with  a  strong  solution  of  kerosene  emulsion.  This  method 
is  specially  recommended  for  the  protection  of  small  plantations, 
groves,  or  shade  trees.  The  work  should  be  done  in  the  fall  or  winter, 
not  earlier  than  November  1  and  not  later  than  April  1. 

Great  care  should  be  exercised  as  to  the  time  of  year  when  locust 
trees  are  cut  for  any  purpose  in  order  that  the  hibernating  borers  may 
be  destroyed.  Except  for  the  purpose  of  destroying  the  borers  in  the 


Yearbook  U.  S.  Dept.  of  Agriculture,  1910. 


PLATE  XXIII. 


CZ-- 


WORK  OF  THE  BLACK-HORNED  PlNE  BORER  (CALLIDIUM 
ANTENNATUM). 

[Section  of  spruce  rustic  work,  showing  larval  mines  on  surface 
of  wood,    a,  Entrance  hole  of  larva  into  wood.     (Original.)] 


INJURIES    BY    KUUJNDHiiAD^D 


wood,  cutting  should  always  be  done  between  the  1st  of  October  and 
the  1st  of  April  and  the  bark  removed,  and  the  tops  and  thinnings 
burned.  When  it  is  necessary  to 
cut  trees  between  the  1st  of  May 
and  the  middle  of  September, 
the  tops  should  be  burned  and 
the  logs  either  barked,  or  sub- 
merged in  water  for  a  few  days 
before  they  are  shipped  or 
manufactured.1 

THE  PAINTED  HICKORY  BORER. 

(Cyllene  caryce  Galian.2) 

The  painted  hickory  borer  is 
a  close  relative  of  the  locust 
borer  and  one  of  the  commonest 
and  most  destructive  borers  in 
dead  and  dying  hickory,  the 
larval  mines  often  riddling  the 
sapwood  and  sometimes  the 
heartwood  as  well.  Besides 
hickory,  it  attacks  walnut, 
honey  locust,  mulberry,  and 
Osage  orange,  but  never  attacks 
the  black  locust.  Its  range  ap- 
pears to  be  coextensive  with  that 
of  hickory. 

The  larva  is  a  creamy  white, 
compact  grub  and  has  three 
pairs  of  legs.  The  adult  so 
closely  resembles  the  adult  of 
the  locust  borer  (fig.  22,  b)  as 
to  be,  to  the  ordinary  eye,  indis- 
tinguishable from  it.  The  sea- 
sonal history,  however,  is  quite 
different  from  that  of  the  locust 
borer.  The  adults  fly  and  de- 
posit eggs  in  May  and  June  and 
do  not  appear  at  other  seasons 
of  the  year.  The  egg  is  laid  in  a 
crevice  of  bark,  and  the  young  larva  hatching  therefrom  proceeds  to 
the  inner  bark  and  soon  enters  the  wood.  If  a  great  number  of  larvae 

1  See  U.  S.  "Dept.  of  Agriculture,  Bureau  of  Entomology,  Bui.  58,  Part  I,  and  Bui.  58, 
Part  III. 

2  Known  for  many  years  under  the  name  of  Cyllene  pictus  Drury. 


FIG.  23. — Work  of  the  painted  hickory  borer 
(Cyllene  caryw).  Section  of  hickory  log 
showing  larval  mines.  (Original.) 


350  YEARBOOK   OF   THE  DEPARTMENT   OF   AGRICULTURE. 

are  present  in  the  same  piece  of  wood,  the  solid  wood  is  often  literally 
honeycombed  with  their  mines  (fig.  23).  Pupation  takes  place  in  the 
wood  and  the  adult  beetle  usually  emerges  in  May  or  June  of  the 
year  following  that  in  which  the  egg  is  laid. 

It  has  been  found  that  hickory  cut  between  August  10  and  No- 
vember 1  usually  is  not  damaged  by  this  borer.  Therefore,  where 
much  damage  occurs  from  this  source,  all  cutting  of  green  timber 
should  be  done  as  nearly  as  possible  within  this  period.  If  it  is 
absolutely  necessary  to  do  the  cutting  in  the  spring  or  early  sum- 
mer, the  bark  should  be  removed  and  the  tops  and  useless  branches 
burned. 

THE  BLACK-HORNED  PINE-BORER. 

(Callidium  antennatum  Newm. ) 

Injuries  by  the  black-horned  pine-borer  to  the  bark  or  sapwood  of 
dead  or  dying  cedar,  juniper,  pine,  and  spruce  are  common  generally 
over  the  United  States.  Often  the  timbers  in  rustic  houses  are  found 
to  be  infested,  and  rustic  work  is  especially  liable  to  injury,  since  the 
presence  of  bark  is  absolutely  necessary  for  the  early  development  of 
the  borer. 

When  first  hatched  from  the  egg  the  larva  feeds  exclusively  on  the 
inner  bark,  making  an  irregular  winding  mine.  Later  it  also  grooves 
the  surface  of  the  wood  (PI.  XXIII)  in  making  its  mine,  thus  com- 
pletely separating  the  bark  from  the  wood,  causing  it  to  become  loose 
and,  in  many  cases,  to  fall  off.  As  the  essential  part  of  rustic  work 
is  the  bark,  this  sort  of  injury  to  it  is  quite  a  serious  matter.  The 
larva  is  an  elongate,  fleshy,  yellowish-white  grub,  usually  about  a 
half  inch  in  length  when  full  grown.  After  working  in  the  bark 
until  a  certain  period  of  development  is  reached,  the  larvae  enter  the 
wood  and  continue  their  mines  there.  Usually  they  do  not  go  deeper 
than  the  sapwood,  except  in  small  stems  or  branches,  where  they 
may  penetrate  the  heartwood.  The  larva  pupates  in  the  wood.  The 
adult  which  finally  emerges  is  a  medium-sized,  robust  beetle,  9  to  14 
mm.  in  length,  blue  to  green  in  color  throughout.  There  appears  to 
be  but  one  generation  a  year.  Adults  fly  and  deposit  eggs  during 
the  months  of  April,  May,  June,  and  July.  The  winter  is  prob- 
ably passed  in  the  larval  stage,  the  adults  emerging  the  following 
spring. 

As  a  preventive  against  injuries  by  this  borer,  cedar,  juniper,  pine, 
and  spruce  should  be  cut  in  the  late  summer,  fall,  or  early  winter. 
If  cut  during  the  period  between  January  and  August,  the  trees 
should  be  barked  when  felled.  In  the  case  of  rustic  work  already  in 
use  when  found  to  be  infested,  some  relief  may  be  secured  by  inject- 
ing bisulphid  of  carbon  into  holes  in  the  bark  through  which  sawdust- 


INJURIES  BY  ROUNDHEADED  BORERS. 


351 


like  borings  fall  out,  and  stopping  up  the  holes  with  putty  or  some 
kind  of  wax.  The  dropping  of  the  sawdust-like  borings  from  the 
logs  or  timbers  always  indicates  the  presence  of  this  or  a  similar  kind 
of  borer. 

THE    CEDAR-TREE    BORER. 

(Hylotrupes  ligneus  Fab.) 

The  cedar-tree  borer  attacks  dead  and  injured  Douglas  fir,  arbor- 
vitse,  red  cedar,  redwood,  western  hemlock,  Engelmann  spruce,  juni- 
per, alpine  fir,  giant  arborvitae, 
white  fir,  bigtree,  and  Arizona 
cypress.  In  some  cases  living, 
healthy  trees  may  be  attacked 
and  killed,  and  in  other  cases 
the  death  and  decay  of  already 
unhealthy  trees  may  be  hastened 
by  this  borer.  This  species  also 
seriously  injures  the  wood  of 
felled  trees  for  commercial  pur- 
poses and  the  bark  and  wood  of 
those  used  for  rustic  work.  Its 
occurrence  is  general  over  the 
United  States  where  its  host 
plants  occur. 

The  larva  (fig.  24,  b)  is  a  yel- 
lowish-white grub  about  half  an 
inch  in  length  when  mature, 
tapering  from  the  prothoracic 
segment  to  the  last  three  ab- 
dominal segments,  which  are 
slightly  larger  than  those  imme- 
diately preceding.  The  adult 
(fig.  24,  a)  is  a  beetle  varying 
from  7  to  16  mm.  in  length. 
The  elytra  or  wing  covers  are 
sometimes  marked  with  alter- 
nate transverse  bands  of  red  and 
black,  and  sometimes  are  entirely 
black  or  reddish  brown.  Apparently  there  is  but  one  generation 
a  year.  The  egg  is  laid  in  crevices  of  the  bark  in  spring  or  sum- 
mer. The  larva  hatching  from  the  egg  excavates  a  winding,  irregu- 
lar mine  in  the  inner  bark,  scoring  the  wood,  later  entering  the 
sapwood,  and  sometimes  penetrating  to  the  heartwood  (fig.  24). 
Pupation  usually  takes  place  in  the  sapwood,  but  sometimes  occurs 


FIG.  24. — Work  of  the  cedar-tree  borer 
(Hylotrupes  ligneus).  Section  of  Ari- 
zona cypress  showing  larval  mines,  a, 
Adult ;  &,  larva.  Insects  natural  size. 
(Original.) 


352 


YEARBOOK   OF    THE   DEPARTMENT    OF   AGRICULTURE. 


in  the  heartwood  or  even  in  the  bark.  It  appears  probable  that 
the  winter  may  be  passed  either  in  the  larval,  pupal,  or  adult  stage, 
the  larval  stage  evidently  predominating.  The  period  during  which 
adults  emerge  is  fyuite  extended,  apparently  from  March  to  Septem- 
ber, inclusive,  depending  considerably  on  latitude  and  altitude  and 
on  the  stage  of  development  reached  before  hibernation  began  during 
the  previous  winter.  The  same  period  represents  the  time  when  eggs 

are   deposited   for   another   gen- 
eration. 

The  usual  preventive  measures 
are  recommended,  i.  e..  remov- 
ing the  bark  from  trees  when 
felled  or  treating  rustic  work 
as  recommended  for  the  black- 
horned  pine  borer,  except  those 
felled  in  late  fall  or  early  winter, 
which  should  not  be  injured  by 
this  borer. 

THE    AVESTERN    CEDAR    BARK-BORER. 

(Hylotrupes  ametliy 'stiiuis  Lee.) 

The  western  cedar  bark-borer 
is  a  relative  of  the  preceding, 
the  cedar-tree  borer.  Unlike  the 
latter,  however,  its  range  is  con- 
siderably restricted.  The  rec- 
ords of  the  branch  of  forest  in- 
sect investigations,  Bureau  of 
Entomology,  indicate  that  it  is 
found  only  in  the  Pacific  Coast 
States.  It  is  of  considerable  eco- 
nomic importance,  however,  in 
injuring  the  bark  and  wood  of 
recently  felled  giant  arborvita? 
and  incense  cedar. 

The  larva  (fig.  25,  a)  is  a 
large,  fleshy,  yellowish-white  grub,  provided  with  three  pairs  of 
feet.  The  largest  larvae  are  about  25  mm.  long  at  maturity  and 
about  8  mm.  in  width  at  the  broadest  part  of  the  body,  the  pro- 
thorax.  The  adult  (fig.  25,  I)  is  a  medium-sized  to  large,  robust 
beetle,  12  to  23  mm.  in  length.  The  prothorax  is  black  to  reddish 
brown.  The  elytra,  or  wing-covers,  are  of  a  brilliant  blue  to  vio- 
let color.  The  larva?  mine  in  the  inner  bark,  making  broad  wind- 


FIG.  25. — Work  of  the  western  cedar  bark- 
borer.  (// ylolrupes  ainethystinus).  Sec- 
tion of  incense  cedar  log,  showing  larval 
mines,  a,  Larva ;  ft,  adult ;  c,  entrance 
hole  of  larva  into  wood.  Insects  slightly 
reduced  from  natural  size.  (Original.) 


INJURIES   BY  ROUNDHEADED   BORERS. 


353 


ing  galleries  and  scoring  the  surface  of  the  sapwood,  sometimes 
almost  entirely  separating  bark  from  wood.  They  finally  enter  the 
wood,  sometimes  mining  to  the  heartwood,  where  the  mine  becomes 
longitudinal.  Pupation  takes  place  in  either 
bark  or  wood,  but  usually  in  heartwood.  It 
is  probable  that  there  is  but  one  generation  a 
year  and  that  adults  emerge  and  deposit  eggs 
in  July,  August,  and  September. 

The  same  recommendations  for  preventing 
injury  as  those  given  for  the  cedar-tree  borer 
are  applicable  to  this  species.. 

THE    BANDED    AST!    BORER. 


ru  Say.) 


(Ncocli/tu$ 

Numerous  complaints  have  been  received 
by  the  Bureau  of  Entomology  regarding  seri- 
ous damage  to  ash  lumber  by  the  banded  ash 
borer  and  closely  related  species.  Of  all 
species  concerned,  however,  this  is  apparently 
the  most  destructive,  the  larvse  perforating 
the  sapwood  with  their  mines  (fig.  26)  and 
greatly  depreciating  its  value,  if  not  entirely 
ruining  it.  Besides  ash,  the  borer  attacks  and 
lives  in  mesquite  and,  rarely,  in  white  oak. 

The  larva  is  an  elongate,  footless,  fleshy 
white  grub  about  an  inch  in  length  when 
mature.  The  adult  is  an  elongate  beetle,  15 
to  18  mm.  in  length.  The  ground-color  is 
black,  with  four  yellowish-white  bands  on 
the  elytra  or  wing-covers  and  one  on  the 
{interior  border  of  the  prothorax.  The  tips 
of  the  elytra  are  yellowish  white.  The 
female  beetle  deposits  her  eggs  on  the  bark 
of  dy'mg  or  dead  trees  or  logs.  There  is  but 
one  generation  a  year.  The  adults  usually 
emerge  and  deposit  eggs  in  March,  April,  or 
May.  The  larva.1  mine  in  the  bark  and  sap-  FIG.  26.  —  Work  of  the  banded 
wood  and  pupate  in  the  sapwood.  ^T'^SS^S'  .~ 

Ash  trees  cut  in  the  summer,  fall,  or  early       log  showing  larval  mines. 
winter   are   less   liable   to   attack   from   this 

species  than  those  cut  in  the  spring,  but  even  those  cut  in  the  fall  are 
sometimes  attacked  the  following  spring.  The  best  way  to  prevent 
injury  to  logs  cut  during  the  winter  and  spring,  when  the  logs  are 


354 


YEARBOOK   OF   THE   DEPARTMENT   OF   AGRICULTURE. 


not  to  be  immediately  sawed  into  lumber,  is  to  remove  the  bark  imme- 
diately upon  felling  or  betAveen  the  1st  of  March  and  1st  of  June. 
Placing  the  logs  in  water  after  the  larvae  have  hatched  and  before 
they  have  entered  the  wood  is  also  effective. 

THE  RED-HEADED  CLYTUS. 

crythroceplialus  Fab.) 


The  red-headed  clytus  is  a  close  relative  of  the  banded  ash  borer 
and  does  considerable  damage  to  the  wood  of  dead  and  dying  ash,  as 

well  as  to  a  number  of  other  trees.  The 
list  of  its  host  plants  includes  ash,  horn- 
beam, hickory,  maple,  sweet  gum,  chest- 
nut, cypress,  hackberry,  black  walnut. 
dogwood,  black  oak.  persimmon,  peach, 
locust,  sassafras,  holly,  mesquite,  Texas 
redbud,  pine,  Kentuck}^  coffee  tree. 
lilac,  honeysuckle,  and  grapevine. 

The  larva  is  a  slender,  white,  footless 
grub  of  varying  length  when  mature. 
the  average  length  at  this  stage  being, 
perhaps,  about  15  mm.  The  adult  is  ti 
slender  beetle,  6  to  16  mm.  in  length. 
The  head  and  prothorax  are  red.  The 
anterior  part  of  the  elytra  is  reddish, 
shading  into  dark  brown  or  black  pos- 
teriorly. The  elytra  bear  four  pairs  of 
yellow  bands,  the  first  pair  being  at  the 
extreme  base.  There  is  but  one  genera- 
tion a  year.  It  appears  that  eggs  may 
be  laid  anywhere  from  March  to  Sep- 
tember. The  adult  female  deposits  the 
egg  in  a  crevice  of  bark  on  a  dead  or 
dying  tree  or  log.  The  young  larva, 
hatching  from  the  egg,  mines  first  in  the 

inner  bark  and  later  continues  the  mine  in  the  sapwood,  thus  injuring 
the  wood  for  commercial  purposes  (fig.  27).  Pupation  takes  place 
in  the  sapwood.  The  adult  emerges  from  the  tree  or  log  the  follow- 
ing spring  or  summer  after  the  egg  is  laid.  This  species  is  common 
from  the  District  of  Columbia  to  Ohio,  and  south  to  Texas. 

The  same  preventive  measures  as  those  given  for  the  banded  ash 
borer  apply  to  this  species  except,  it  will  be  noted,  that  the  egg-laying 
period  of  this  species  is  much  longer  than  that  of  the  banded  ash 


FIG.  27. — Work  of  the  red-headed 
clytus  (Xeuclytus  ei'i/tlircxepha- 
1ns)  Sections  of  hickory  log 
showing  :  a,  Larval  mines  on  sur- 
face of  wood  ;  6,  larval  mines  in 
the  wood ;  c,  entrance  hole  of 
larva  into  wood.  (Original.) 


INJURIES   BY   ROUNDHEADED   BORERS. 


355 


borer,  so  that  there  is  scarcely  any  season  of  the  year  when  trees  may 
be  cut  and  left  with  bark  on,  without  danger  of  being  damaged  by 
this  borer. 

THE   OAK   PRUNEK. 

(Elaphidion  viUosum  Fab.) 

In  the  oak  primer  we  have  a  species  which  attacks  only  twigs  or 
small  branches  on  living  and  injured  trees,  causing  them  to  break  and 
fall  to  the  ground.  If  occurring  in  large  numbers  it  is  of  consider- 
able economic  importance,  in  retarding 
the  growth  of  twigs  and  branches.  Be- 
sides oak.  this  species  attacks  sassafras, 
black  walnut,  hackberry,  sweet  gum,  hick- 
ory, and  maple.  Its  range  extends  from 
Pennsylvania  to  South  Carolina,  and  as 
far  west  as  New  Mexico. 

The  larva  (fig.  28,- a)  is  a  very  slender 
white  grub  about  one-half  inch  in  length. 
The  adult  is  a  slender,  shining,  brown 
beetle  (fig.  28,  &),  11  to  16  mm.  in  length, 
rather  sparsely  clothed  with  gray  pubes- 
cence, each  elytron  terminating  in  two 
spines  of  about  equal  length.  Adults  fly 
in  March,  April,  May,  and  June,  during 
which  time  oviposition  takes  place  upon 
the  twigs  or  branches. 

The  young  larva,  after  hatching  from 
the  egg,  first  mines  in  the  inner  bark, 
then  enters  the  wood  and  girdles  the 
twig  or  branch  by  boring  around  it  sev- 
eral times  in  the  same  place  (fig.  28), 
leaving  the  bark  and  usually  some  of  the 
wood  intact.  The  larva  then  mines  in 

the  center  of  the  twig  beyond  the  girdle.  The  twig  is  usually 
broken  off  at  the  girdle  by  the  wind  and  falls  to  the  ground,  carrying 
the  larva  with  it.  Pupation  takes  place  in  the  center  of  the  twig. 
There  is  apparently  one  generation  a  year,  the  adult  usually  emerging 
in  March,  April,  May,  or  June  of  the  year  following  that  in  which 
the  egg  is  laid. 

When  this  species  occurs  in  large  enough  numbers  to  be  injurious, 
the  fallen  twigs  and  recently  killed  twigs  still  on  the  trees  should  be 
gathered  and  burned  in  the  fall  in  order  to  destroy  the  larvae  and 
pupse  in  them. 


FIG.  28 — Work  of  the  oak 
primer  (Elaphidion  rillosum). 
Oak  branch  which  has  hcen 
pruned,  showing  larval  mines. 
a,  Larva ;  6,  adult.  Insects 
natural  size.  (Original.) 


356 


YEARBOOK   OF    THE   DEPARTMENT    OF   AGRICULTURE. 


THE    HICKORY    TWIG-GIRDLER. 

(Oncidcrcs  cingnlata  Say.) 

The  work  of  the  hickory  twig-girdler,  like  that  of  the  oak  primer, 
is  confined  to  the  twigs  and  branches,  and  is  often  quite  injurious. 
Only  living  trees  are  attacked.  The  list  of  host  plants  includes 
hickory,  basswood,  poplar,  dogwood,  black 
gum,  elm,  persimmon,  and  acacia.  The  range 
of  this  species  extends  from  the  eastern  United 
States  to  Arkansas  and  Kansas. 

The  larva  is  a  footless  white  grub  about  half 
an  inch  or  more  in  length  when  mature.  The 
abdominal  segments,  except  the  last  two,  bear 
minute  granules,  both  above  and  below.  The 
adult  (fig.  29,  a)  is  a  stout  beetle.  12  to  14  mm. 
in  length,  dark  gray  to  reddish  brown  in  color. 
The  flight  of  the  adults  and  the  deposition  of 
eggs  usually  occur  in  August  or  September. 
The  adult  female  punctures  the  branch  or  twig 
and  deposits  an  egg  in  each  puncture.  She 
then  gnaws  off  the  bark  and  outer  wood  at  a 
point  on  the  branch  below  where  the  eggs  are 
laid,  completely  circling  the  limb  and  causing 
that  portion  of  it  beyond  the  girdle  to  die  (fig. 
29).  The  eggs  hatch  and  the  larva?,  after  min- 
ing in  the  inner  bark  (fig.  29,  6),  bore  to  the 
center  of  the  branch,  where  pupation  takes 
place  in  the  larval  mine,  little  if  any  protective 
device  in  the  way  of  a  pupal  chamber  being 
made.  Probably  most  of  the  infested  twigs 
and  branches  fall  to  the  ground  before  the 
larva?  complete  their  development,  though  some 
do  nor.  It  has  been  found  that  in  the  infested 
branches  which  do  not  fall  the  larvae  seldom 
complete  their  development  to  the  adult  stage 
unless  the  branches  are  in  a  shaded  position. 
Likewise,  few  adults  are  produced  from 
branches  which  are  freely  exposed  to  the  sun  after  falling.  This 
insect  reaches  its  best  development  in  shaded  twigs  or  branches,  or 
those  partially  covered  by  leaves  or  vegetation.  In  North  Carolina 
the  larvae  begin  to  pupate  about  August  1  of  the  year  following  that 
in  which  the  eggs  were  laid,  most  of  the  adults  probably  emerging 
in  September.  The  winter  is  therefore  passed  in  the  larval  state. 


FIG.  29  — Work  of  the 
hickory  twig  -  girdler 
(Oncideres  cingulata) . 
Acacia  branch  showing 
girdle,  and  larval  mines 
in  bark  and  outer  wood. 
Insect  natural  size. 
(Original.) 


INJURIES   BY   ROUNDHEADED    BORERS.  357 

The  work  of  the  insect  is  not  confined  to  the  large  trees,  but 
straight  young  seedlings  from  4  to  10  feet  high  are  sometimes 
attacked  and  the  entire  top  taken  off,  resulting  in  the  removal  of 
about  2  feet  of  the  new  growth,  usually  nearly  two  years'  incre- 
ment. The  adult  beetle  apparently  injures  the  smaller  twigs  by 
feeding  upon  the  bark  without  depositing  eggs  in  them. 

Where  this  species  occurs  in  destructive  numbers  it  is  advisable 
to  collect  and  burn  the  pruned  twigs  and  branches.  This  should  be 
done  several  times  between  October  1  and  August  1  of  the  following 
year — once  just  before  the  leaves  fall,  once  early  in  the  spring 
before  vegetation  starts,  and  again  in  the  summer  during  June  or 
July.  The  twigs  which  first  fall  are  quite  apt  to  be  almost  hidden 
by  fallen  leaves  and  quite  difficult  to  find  in  the  spring. 

SUMMARY. 

Ill  general,  roundheaded  borers  are  elongate,  fleshy,  yellowish- 
white  grubs,  which  hatch  from  eggs  deposited  by  the  parent  beetles 
in  or  upon  the  bark  or  wood  of  the  host  plant.  The  grubs  finally 
change  to  pupre  and  these  in  turn  change  to  adults  or  beetles.  The 
young  adults  in  time  emerge  from  the  host  and  deposit  eggs  in  or 
upon  other  host  plants;  and  so  the  life  cycle  goes  on.  Usually  there 
is  but  one  generation  a  year,  but  in  some  species  there  may  be  two 
generations  a  year,  and  in  other  species  it  may  take  longer  than  a 
year  for  a  single  generation  to  develop. 

Great  damage  is  done  to  living  and  felled  trees,  and  to  standing 
dead  trees,  by  this  class  of  borers.  In  some  cases  the  borers  confine 
themselves  to  the  bark,  while  in  others  they  enter  the  wood.  The 
remedy  in  each  case  depends  upon  the  habits  and  character  of  work 
of  the  species  under  consideration. 

The  western  larch  bark-borer  attacks  perfectly  healthy  western 
larches,  making  winding,  irregular  galleries  in  the  inner  bark,  thus 
cutting  off  the  flow  of  sap  and  killing  the  trees.  The  methods  of 
control  are  preventive.  No  attempt  is  made  to  save  a  tree  which  has 
once  become  badly  infested.  After  becoming  infested,  trees  should 
be  felled  and  barked  and  the  bark  burned  before  the  following 
May  15.  A  few  healthy  trees  felled  in  May  or  June,  near  those  in- 
fested, should  attract  the  beetles  which  would  otherwise  deposit 
eggs  in  healthy  trees.  Before  the  following  spring  the  bark  should 
be  stripped  from  these  trap  trees  and  burned. 

The  southern  pine  sawyer  is  very  destructive  to  felled  pine  timber 
in  the  Southern  States,  making  large,  unsightly  holes  in  the  sap- 
wood  and  greatly  reducing  in  value  a  considerable  percentage  of 
each  log  infested.  Injury  by  this  species  may  be  prevented  in  two 
ways.  First,  by  placing  infested  logs  in  water  while  the  larvse  are 


358          YEARBOOK   OF   THE   DEPARTMENT   OF   AGRICULTURE. 

still  in  the  bark  and  before  they  have  entered  the  wood ;  and  second. 
by  removing  the  bark  from  the  logs  before  the  larvse  have  entered 
the  wood. 

The  locust  borer  is  a  serious  and  destructive  enemy  of  the  black 
or  yellow  locust.  Its  first  work  is  in  the  inner  bark.  Later  it  enters 
the  wood,  where  its  most  destructive  work  is  done,  either  by  so  honey- 
combing the  wood  as  to  cause  the  death  of  branches  or  small  trees, 
or  by  injuring  the  wood  for  commercial  purposes.  Hibernating 
larvae  may  be  killed  by  spraying  the  trunks  and  branches  with  a 
strong  solution  of  kerosene  emulsion.  Except  for  the  purpose  of 
destroying  the  borers  in  the  wood,  cutting  should  always  be  done 
between  October  1  and  April  1,  the  bark  removed,  and  the  tops  and 
thinnings  burned.  When  it  is  necessary  to  cut  trees  between  May  1 
and  the  middle  of  September  the  tops  should  be  burned  and  the 
logs  either  barked  or  submerged  in  water  for  a  few  days  before  they 
are  shipped  or  manufactured. 

The  painted  hickory  borer  attacks  dead  and  dying  hickory,  walnut, 
honey  locust,  mulberry,  and  Osage  orange,  the  larval  mines  often 
riddling  the  sapwood  and  sometimes  the  heartwood  as  well.  To  pre- 
vent the  spread  of  this  species,  all  cutting  of  green  timber  should 
be  done  between  August  10  and  November  1.  Timber  which  must 
be  cut  in  spring  or  early  summer  should  have  the  bark  removed  and 
the  tops  and  useless  branches  burned. 

The  black-horned  pine-borer  is  an  enemy  of  dead  or  dying  cedar, 
juniper,  pine,  and  spruce.  Eustic  work  is  specially  liable  to  injury 
from  this  source.  As  a  preventive  against  injuries  by  this  species, 
cedar,  juniper,  pine,  and  spruce  should  be  cut  in  late  summer,  fall, 
or  early  winter.  If  cut  between  January  and  August  the  trees 
should  be  barked  when  felled.  In  the  case  of  injuries  to  rustic  work, 
an  injection  of  bisulphid  of  carbon  and  the  plugging  up  of  the  holes 
with  wax  or  putty  is  recommended. 

-The  cedar-tree  borer  attacks  dead  and  injured  Douglas  fir,  arbor - 
vitse.  red  cedar.  redAvood,  western  hemlock,  Engelmann  spruce,  juni- 
per, alpine  fir,  giant  arborvita?,  white  fir,  bigtree,  and  Arizona  cypress. 
Like  the  black-horned  pine-borer,  it  is  injurious  to  rustic  work.  The 
usual  preventive  measures  are  recommended,  i.  e.,  removing  the  bark 
from  trees  when  felled,  or  treating  rustic  work  as  recommended  for 
the  black-horned  pine-borer. 


Makers 
Syracuse,  N.  Y. 

PAT.  JJN,  21.  1908 


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